Giant barred frog

Giant barred frog Photo: B Manning, EHP

Common name: giant barred frog

Scientific name:Mixophyes iteratus

Family: Myobatrachidae (Australian water frogs)

Conservation status: This species is listed as Endangered in Queensland (Nature Conservation Act 1992) and nationally (Environment Protection and Biodiversity Conservation Act 1999). It is ranked as a medium priority under the Department of Environment and Heritage Protection Back on Track species prioritisation framework.

Description

A very large frog up to 120 mm with a pointed snout and well developed hind legs. The dorsal surface is dark olive to black, with darker blotches and an irregular dark vertebral band commencing between the eyes and continuing posteriorly. A dark stripe runs from the snout, through the eye and above the tympanum (hearing organ), terminating at a point above the forelimb.

There are irregular dark spots or mottling on the flanks. The limbs have a series of dark and pale crossbars of similar width. The hidden part of the thigh is black with a few large, yellow spots. The ventral surface is white to yellow with fine mottling on the chin. The pupil is vertical, while the iris is pale silvery-white to pale gold above, darker in the lower portion. The fingers lack webbing, while the toes are fully webbed, with only the last two joints of the fourth toe free. The skin is finely granular above, smooth below (Barker et al. 1995; Cogger 2000; Straughan 1968).

Habitat and distribution

This species occurs along shallow rocky streams in rainforest, wet sclerophyll forest and farmland from 100 to 1000 m or deep, slow moving streams with steep banks in the lowlands.

The giant barred frog occurred along streams in the coastal ranges and lowlands from Belli Creek near Eumundi, in south east Queensland to Warrimoo in mid-east New South Wales (26° 31'S, 152° 49'E - 33° 43'S, 150° 36'E).

This species has experienced significant population declines in the north and south of its range during the late 1980's. In south-east Queensland it is currently known from scattered locations in the catchments of the Mary, Upper Stanley, Caboolture and Coomera Rivers. Recent surveys have failed to locate the species in historical sites in the Bunya Mountains, Cunningham's Gap and Main Range. The previously thought extinct population in the Conandale Range appears to be recovering.

Life history and behaviour

Relatively little is known regarding the reproductive biology of this species. A gravid female was found to carry 4184 eggs with a mean diameter of 1.6 mm. Larvae are present throughout the year and probably over-winter. Laboratory reared metamorphs reach 28-30 mm (Hero & Fickling 1996; Straughan 1966).

The tadpole has not been formally described. They are large and take a form commonly seen in tadpoles that inhabit free-flowing water, with a suctorial mouth, muscular tail and reduced fins.

Threatening processes

The primary cause of decline in this species is suspected to be the chytrid fungus disease. Current threats include the chytrid fungus, loss and fragmentation of habitat, changes in water quality and flow regimes, introduced fish, feral pigs, domestic stock trampling and fouling streams and weed invasion of waterways.

Hines H, Mahony M and McDonald KR. 1999. An Assessment of Frog Declines in Wet Subtropical Australia. In Campbell, A (ed), 'Declines and Disappearances of Australian frogs'.(Environment Australia, Department of the Environment and Heritage: Canberra). 234 pp.

Ingram GJ and McDonald KR. 1993. An update on the decline of Queensland's frogs. Pp 297-303 In Lunney, D. and Ayers, D. (eds), Herpetology in Australia. A diverse discipline. (Royal Zoological Society of New South Wales: Mosman). 414pp.

Mahony MJ. 1993. The status of frogs in the Watagan Mountains area of the Central Coast of New South Wales. Pp. 257-264 In Lunney, D. and Ayers, D. (eds), Herpetology in Australia. A diverse discipline. (Royal Zoological Society of New South Wales: Mosman). 414pp.

Straughan IR. 1968. A taxonomic review of the genus Mixophyes (Anura, Leptodactylidae). Proceedings of the Linnean Society of N.S.W. 93:52-59.